Facebook app built to keep kids safe could be used to introduce them to strangers

'Technical error' allowed people to get around privacy and safety protections

The Facebook logo is displayed during the F8 Facebook Developers conference on April 30, 2019 in San Jose, California (Justin Sullivan/Getty Images)

Facebook's app specifically created to stop children chatting with strangers had a bug that allowed them to do just that.

The Facebook Messenger Kids service was made to allow parents to decide and monitor who their children were chatting to. In so doing, the company hoped to get young people onto its service, by promising their parents they would be looked after.

But the app had a major flaw that allowed children to get around that protection, and talk to people that their parents had not permitted them to.

The bug was revealed after Facebook sent messages to parents informing them that their children could have been talking to strangers on the app.

Parents should be able to approve every person that talks to their child, so that they can only message people who have been vetted by the adult who looks after them. The bug allowed people to get around that problem by letting a user who opened a group chat invite anybody they liked, meaning that they could find themselves in conversations with strangers their parents knew nothing about.

"Hi [PARENT]," the letter, which was first reported by The Verge, began.

"We found a technical error that allowed [CHILD]’s friend [FRIEND] to create a group chat with [CHILD] and one or more of [FRIEND]’s parent-approved friends. We want you to know that we’ve turned off this group chat and are making sure that group chats like this won’t be allowed in the future. If you have questions about Messenger Kids and online safety, please visit our Help Center and Messenger Kids parental controls. We’d also appreciate your feedback."

Facebook said that the issue only affected a small number of chats and that it had now been turned off and fixed.

It isn't clear how long the issue has been present. Messenger Kids' group chat feature was introduced at the end of 2017.

Facebook's kids app was launched specifically to get around limitations placed on childrens' use of social media, which usually ban young people under the age of 13 from using chat apps.